The object of this study was to determine whether: 1) the sulfation of cholecystokinin octapeptide (CCK) could be demonstrated in brain; 2) whether the rate of CCK synthesis could be calculated using sulfate incorporation as a method; 3) whether inhibitors could be found which would permit a pharmacological assessment of CCK turnover and the physiological role of CCK in brain cortex. Goals 1 and 2 were fully met during the previous fiscal year, and the data were summarized for publication. Goal 3 was approached via study of several compounds obtained from commercial sources or synthesized by Dr. K.L. Kirk of NIADDKD. None of the compounds tested were able to completely inhibit sulfation at doses which were not toxic. These data have been accepted for publication.